The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a touch detection function capable of detecting an external proximity object.
Recently, a touch detection device capable of detecting an external proximity object, which is called a touch panel, has attracted attention. The touch panel is mounted or integrated on a display device such as a liquid crystal display device. As such, the liquid crystal display device in which the touch panel is mounted or integrated on the display device, that is, the liquid crystal display device having the touch detection function, displays various button images or the like on the display device and detects the proximity of an external object to the button images through the touch panel. As a result, the touch panel can be used as means of data input, instead of usual mechanical buttons. Since such a liquid crystal display device having the touch detection function does not necessarily require means of data input, such as a keyboard or a mouse, the use of the liquid crystal display device tends to expand even in a portable information terminal such as a mobile phone, as well as a computer.
As a detection method of the touch detection device, there are several methods such as an optical type, a resistance type, and a capacitance type. Among the methods, since the capacitance type touch detection device has a relatively simple structure and has a low power consumption, the capacitance type touch detection device is used in a portable information terminal or the like. The capacitance type touch detection device is disclosed in Japanese Patent Application Laid-Open Publication No. 2012-230657 (Patent Document 1).
In addition, in the liquid crystal display device, there is a growing demand for an increase in a size of a display surface and a high definition. Accordingly, there is a demand for an increase in size and a high precision in the touch panel. Furthermore, it is required to narrow a frame so as to achieve the increase in the size of the display surface while suppressing the increase in the size of the liquid crystal display device. In other words, it is required to narrow a frame that surrounds the display surface of the liquid crystal display device.